Magnetic stimulation: A novel method for inducing evacuation of the neuropathic rectum and urinary bladder in a canine model

Objectives, To study the effect of sacral magnetic stimulation (MS) on the neuropathic rectum and urinary bladder in dogs. It has been demonstrated in a canine model and in humans that sacral MS of both the empty and full rec tum effected a significant increase in rectal and vesical pressures. Evacua tion of the full rectum, as well as balloon expulsion, were achieved. Methods, In 15 dogs, bilateral pelvic ganglionectomy was carried out, and r ectal and vesical denervation was confirmed by bethanechol and atropine tes ting. Sacral MS of the empty and full rectum and urinary bladder were perfo rmed by means of a magnetic stimulator and coil. The electromyographic (EMG ) response of the rectus abdominus muscles to sacral MS was recorded. Results. After pelvic ganglionectomy, the rectal, vesical, anal, and urethr al pressures revealed a significant decrease (all P < 0.05). On sacral MS o f the empty rectum and urinary bladder, rectal and vesical pressures increa sed (both P < 0.001) and anal and urethral pressures did not change (both P > 0.05). Atropine injection abolished the rectal and vesical response to s acral MS; bethanechol did not. During sacral MS, no EMG activity of the rec tus abdominus muscles was recorded. Intermittent sacral MS of the full rect um and urinary bladder raised rectal and vesical pressures (both P < 0.001) and effected evacuation. Conclusions. Sacral MS causes evacuation of the neuropathic rectum and urin ary bladder in a canine model. The technique is simple, noninvasive, nonrad iologic, and cost-effective and has no adverse effects. It is suggested tha t it be used for evacuation of the neuropathic rectum and urinary bladder i n patients with spinal cord injury. (C) 1999, Elsevier Science Inc.